一种消除PWM逆变器输出共模电压的前馈有源滤波器

A novel feed-forward-type active filter to eliminate common-mode voltage generated by a PWM inverter

提出了一种消除PWM逆变器输出共模电压的前馈有源滤波器,包括无源共模电压检测网络,推挽电路以及四绕组共模变压器。滤波器输出与共模电压幅值相同极性相反的补偿电压,将其叠加到逆变器输出上,从而达到消除共模电压的目的。给出了部分滤波器参数的确定方法。结果表明,该滤波器可以显著地抑制电机端共模电压,从而减小了变频器输出的负面影响。

A novel feed-forward-type active filter, which consists of a passive common-mode voltage detection network, a push-pull circuit, and a four-winding transformer, is presented to eliminate common-mode voltage generated by a PWM inverter. A compensating voltage with the same amplitude but with opposite polarity is imposed to the commonmode voltage. Some design considerations of the filter are also given. Simulation and experiment results confirm the validity of the proposed filter that the common-mode voltage at motor terminal is eliminated almost completely and the shaft voltage and bearing current are also decreaced.